From an upcoming episode of PBS's NOVA scienceNOW on the inner workings of animal minds comes an astounding bit of avicular, WWII-era trivia:

During World War II, the same government agency that developed the atomic bomb was also secretly planning "Project Pigeon." Pigeons were trained to ride inside missiles and guide them by pecking them on a screen. In 1944, the project was cancelled in favor of other secret research - radar.